1665.5 

COLL 

c.3 


RS,TY  OF  ILLINOIS-URBANA 


3  0112  121926353 


STATE  OF  ILLINOIS 


".LINOIS 


FEB  3  1988 


Department  of  Registration  and  E|L4>lfl0IS  STATE  LIBRARY 


A.  M.  Shelton,  Director,  Sirinckieijj 


STATE  GEOLOGICAL  SURVEY  DIVISION 


M.  M.  Leighton,  Chief,  Urban  a 

PRESS  BULLETIN 

(For  immediate  release) 


discarded 

Apk  1986 


May  17,  1924 


19551  L 


EXTENSION  OF  ALLENDALE  OIL  FIELD 


By  D.  M.  Collingwood 


The  discovery  in  1922  of  the  flowing  well  on  the  Della 
Wright  farm  in  sec.  8,  T.  1  N.,  R.  12  W.  initiated  an  active 
drilling  compaign  in  the  area  surrounding  the  Allendale 
oil  field  in  Wabash  County.  In  the  hope  of  being  able  to 
aid  the  operators  in  testing  more  efficiently  the  possibili¬ 
ties  of  the  extension  of  the  Allendale  oil  field,  the  Illinois 
Geological  Survey  made  a  study  of  conditions  in  the  area 
in  1923.  A  detailed  report  embodying  the  results  of  the 
field  investigation  is  being  prepared,  but  in  order  to  hasten 
the  availability  of  certain  outstanding  points  of  informa¬ 
tion  which  may  prove  helpful  in  furthering  exploratory 
drilling  this  spring,  this  press  bulletin  is  issued.  Paucity 
of  accurate  and  detailed  logs,  and  a  general  neglect  on  the 
part  of  drillers  to  save  cores  and  samples,  which  serve  as 
the  most  reliable  source  of  information,  rendered  definite 
correlation  difficult. 


STRUCTURAL  RELATIONS  OF  ALLENDALE  OIL  FIELD 

The  Allendale  oil  field  is  situated  at  the  southern  ex¬ 
tremity  of  the  southeastern  Illinois  oil  fields,  and  is  struc¬ 
turally  associated  with  the  same  major  structure — the  La¬ 
Salle  anticlinal  uplift — that  gives  rise  to  the  main  oil  field. 
Although  this  anticlinal  structure  continues  with  a  region¬ 
al  southward  pitch  in  Wabash  County,  its  crest  broadens 
into  several  radiating  folds  centering  in  the  neighborhood 
of  Allendale,  and  includes  wide  terrace-like  areas  on  its  west¬ 
ward  flank  (PI.  1).  The  main  production  has  been  found 
associated  with  small  domings  caused  by  minor  folding, 
on  two  step-like  terraces  situated  generally  just  above  the 
abrupt  change  to  a  steep  north-west  flank  dip. 


2 


It  has  been  recognized,  however,  that  structure  is  not 
the  sole  consideration  in  locating  areas  favorable  to  oil 
accumulation  in  this  field.  Although  holes  drilled  to  the 
east  and  north  of  the  producing  fields  are  probably  not 
located  exactly  on  the  anticlinal  crest,  they  are  structurally 
higher  than  the  terraces,  and  expectation  of  production, 
from  a  structural  viewpoint,  would  have  been  justified. 
However,  dry  holes  and  only  small  showings  of  oil  have 
been  the  results  to  date. 

STRATIGRAPHIC  POSITION  AND  DESCRIPTION  OF 
OIL-BEARING  STRATUM 

The  sand,  locally  called  the  Biehl  sand,  is  found  at 
a  depth  of  1400  to  1600  feet,  and  lies  about  125  feet  below 
the  top  of  the  Chester  series  of  the  Mississippian  system 
which  is  immediately  overlain  by  the  basal  salt  water  sand 
of  the  Pennsylvanian  system. 

Examination  of  cuttings  from  the  sand  stratum  of 
some  producing  wells  revealed  the  fact  that  in  places  the 
Biehl  sand  consists  of  relatively  thin  beds  of  fairly  well 
sorted  sand,  the  maximum  grains  being  of  medium  size. 
These  beds  are  quite  porous  and  contain  the  oil  pay.  They 
are  interbedded  with  hard  sandstone,  composed  of  very 
poorly  sorted  sand  ranging  in  sizes  of  grain  from  medium 
to  very  fine.  This  rock  is  practically  non-porous.  In  some 
places  the  drill  cuttings  are  broken  in  the  form  of  chips 
instead  of  grains,  and  the  sandstone  has  been  logged 
erroneously  as  “lime”  by  many  drillers.  Some  of  the  rock 
contains  particles  so  small  that  it  might  easily  be  called  a 
coarse  shale  or  siltstone. 

LENTICULAR  CHARACTER  OF  OIL  SAND 

The  abrupt  change  laterally  from  well  sorted  sand¬ 
stone  to  hard,  non-porous  siltstone  in  some  places  explains 
the  fact  that  holes  offsetting  producing  wells  in  the  Biehl 
sand  have  proved  to  be  dry.  The  porous  beds  or  parts  of 
the  sand  bed  are  apparently  lenticular.  The  accumulation 
of  oil,  therefore,  is  dependent  not  only  upon  favorable 
structure  but  also  upon  the  existence  of  porous  lenses. 
The  presence  or  absence  of  such  lenses  can  not  generally 
be  predicted  in  advance  of  drilling,  and  it  is  recommended 
that  drilling  be  extended  from  a  given  producing  well  on 
favorable  structure  one  location  at  a  time.  However, 
when  the  general  trend  .of  the  zone  characterized  by  len¬ 
ticular  porosity  can  be  determined,  recommendations  of 
locations  within  the  defined  zones  can  be  made  ahead  of 
the  drill. 


Continued  on  page  3 


w. 


2Q 


le  coal  (light  dash  -  and  -  dot  lines)  relative  to  sea  level. 
2  W.  will  be  indicated  on  Plate  II  of  main  report. 


.-1000 


v  Structure  contours  on  cop 
ol  Biehl  sand 


400 


Structure  contours  on  top 
of  Fr  toads  villc  coni 


Iuilex  Dumber  to  wells 
listed  tn  Tabic  1 


LEGEND 

Producing  wed 

Abandoned  veil 

Dry  bole 

Show  of  oil 


/ 

l-NDALE 


T. 

2 

N. 


T. 

1 

N. 


Typical  driller’s  log  in 
sec.  5,  T.  1  N.,  R.  12  W. 


Plate  1.  Structure  map  of  Allendale  oil  field,  showing  contours  on  Biehl  sand  (heavy  lines)  and  contours  on  Friendsville  coal  (light  dash  -  and  -  dot  lines)  relative  to  sea  level. 
Index  numbers  refer  to  wells  which  will  be  listed  in  main  report.  Wells  located  in  secs.  3,  4,  5,  8,  9,  and  10,  T.  IN.,  R.  12  W.  will  be  indicated  on  Plate  II  of  main  report. 


3 

ORIGIN  OF  THE  SAND  LENSES 

It  is  suggested  that  the  local  sorting  of  the  sand  may 
be  attributed  to  the  action  of  waves  and  shore  currents 
during  the  time  of  sand  deposition.  Although  most  of  the 
uplift  was  post-Pennsylvanian,  there  is  evidence  that  the 
La  Salle  anticline  had  already  been  slightly  uplifted  to  the 
north  in  Chester  time.  In  the  shallow  waters  around  the 
southern  nose  of  the  pitching  anticlinal  axis  of  the  La 
Salle  anticline  it  is  possible  that  currents  paralleling  the 
shores  may  have  had  various  slight  fluctuations  in  intens¬ 
ity  and  direction  due  to  slight  changes  in  the  shore  line 
during  Chester  time.  If  such  fluctuations  were  responsi¬ 
ble  for  the  formation  of  porous  lenses,  in  general  they  prob¬ 
ably  would  occur  as  concentric  zones  around  the  southern 
nose  of  the  anticlinal  structure.  These  zones  would  thus 
tend  to  parallel  the  structure  contours  as  can  be  seen  on  the 
accompanying  structure  map. 

PROMISING  AREAS  FOR  FURTHER  DEVELOPMENT 

Several  promising  anticlinal  areas  occur  outside  the 
present  producing  areas  in  secs.  3,  4,  5,  8,  9,  and  10,  T.  1  N., 
R.  12  W.  There  are  anticlinal  noses  in  the  vicinity  of  (a) 
sec.  36,  T.  2  N.,  R.  12  W.,  and  sec.  1,  T.  1  N.,  R.  12  W. ; 
(b)  secs.  15,  20,  and  21,  T.  1  N„  R.  12  W. ;  (c)  secs.  15, 
22,  and  W.l/2  sec.  27,  T.  1  N„  R.  12  W.;  (d)  common  cor¬ 
ner  of  secs.  8,  9,  16,  and  17,  T.  1  S.,  R.  12  W. ;  (e)  secs. 
26,  27,  28,  and  29,  T.  1  N.,  R.  13  W. ;  and  monoclinal  ter¬ 
races  in  the  vicinity  of  (a)  sec.  18,  T.  1  N.,  R.  11  W. ;  (b) 
secs.  25  and  26,  T.  1  N.,  R.  13  W.,  and  secs.  30  and  31, 
T.  1  N.,  R.  12  W. ;  (c)  sec.  1,  T.  1  S.,  R.  13  W.,  and  E,f/2 
secs.  6,  7,  and  18,  T.  1  S.,  R.  12  W.  If  complete  local  clo¬ 
sures  in  the  Biehl  sand  occur  on  the  monoclinal  terraces, 
the  locations  of  the  crests  will  probably  be  found  slightly 
up  the  regional  dip  from  the  crests  of  the  Friendsville  coal 
closures,  as  shown  on  the  map.  This  is  due  to  a  thickening 
down  dip  of  the  interval  between  the  coal  and  the  Biehl 
sand. 

In  the  consideration  of  all  favorable  structures,  por¬ 
osity  must  be  taken  into  account.  Some  structurally  fav¬ 
orable  areas  have  nearby  dry  holes  in  structural  depres¬ 
sions.  If  these  show  the  existence  of  porous  sand  containing 
salt  water  a  more  favorable  chance  for  pi’oduction  would  be 
found  on  nearby  anticlinal  noses  or  domings.  Areas  that 
have  nearby  dry  holes  without  salt  water  or  small  showings 
of  oil  with  very  hard  and  non-porous  sand,  should  not  be 
selected  until  more  favorable  areas  have  been  drilled. 


4 

ECONOMIC  POSSIBILITIES 


In  the  extension  of  the  field,  26  dry  holes  and  18  pro¬ 
ducing  wells  have  been  drilled.  If  the  cost  of  drilling  pro¬ 
ducing  wells  is  distributed  conservatively  over  their  life; 
if  most  of  the  drilling  cost  of  the  dry  holes  is  charged  to 
the  first  year’s  production  with  the  remainder  charged  to 
the  following  year’s  production  brought  in  on  proven  acre¬ 
age  ;  and  if  the  yearly  cost  of  lifting  and  other  appropriate 
charges  are  also  placed  against  the  first  year’s  production, 
it  will  be  seen  that  the  first  year’s  balance  would  show 
hardly  any  profit.  But  in  the  later  life  of  the  field,  with 
added  production  from  semi-proven  acreage  and  careful 
drilling  on  geologically  recommended  locations,  economic 
gain  to  the  operator  should  be  expected.  With  a  view  to 
furthering  cooperation  between  the  operators  and  the 
Illinois  Geological  Survey,  the  Biehl  sand  should  be  cored 
in  order  that  its  character  may  be  entirely  revealed,  and 
in  addition,  samples  and  logs  should  be  carefully  and  ac¬ 
curately  kept. 


DATE  DUE 


MOV  1  3 

Demco,  Inc.  38-293 


